Method for fabricating a magnetic writer having an asymmetric gap and shields

ABSTRACT

A method and system provide a magnetic transducer. An intermediate including multiple sublayers is provided. A trench is formed in the intermediate layer. A main pole having a bottom, a top wider than the bottom, a first side and a second side opposite to the first side is provided in the trench. An asymmetric gap is provided along the first and second sides of the main pole. The asymmetric gap terminates closer to the top of the main pole along the first side than on the second side. The asymmetric gap has a first thickness along the first side and a second thickness different from the first thickness along the second side. An asymmetric shield is provided on the asymmetric gap. The asymmetric shield includes a half side shield having a bottom between the top and the bottom of the main pole and terminating on the asymmetric gap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser. No. 14/289,345, filed May 28, 2014, entitled “METHOD FOR FABRICATING A MAGNETIC WRITER HAVING AN ASYMMETRIC GAP AND SHIELDS” (WD Docket No. F7080), which claims priority to provisional U.S. Patent Application Ser. No. 61/948,417 (Atty. Docket No. F7080.P), filed on Mar. 5, 2014, which is hereby incorporated by reference in its entirety.

BACKGROUND

FIG. 1 depicts an air-bearing surface (ABS) view of a conventional magnetic recording transducer 10. The magnetic recording transducer 10 may be a perpendicular magnetic recording (PMR) head. The conventional transducer 10 includes an underlayer 12, side gap 14, side shields 16, top gap 17, optional top, or trailing, shield 18 and main pole 20.

The main pole 20 resides on an underlayer 12 and includes sidewalls 22 and 24. The sidewalls 22 and 24 of the conventional main pole 20 form an angle with the down track direction at the ABS. The side shields 16 are separated from the main pole 20 by a side gap 14. The side shields 16 extend at least from the top of the main pole 20 to the bottom of the main pole 20. The side shields 16 also extend a distance back from the ABS. The gap 14 between the side shields 16 and the main pole 20 may have a substantially constant thickness. Thus, the side shields 16 are conformal with the main pole 20.

Although the conventional magnetic recording head 10 functions, there are drawbacks. In particular, the conventional magnetic recording head 10 may not perform sufficiently at higher recording densities. For example, at higher recording densities, a shingle recording scheme may be desired to be sued. In shingle recording, successive tracks partially overwrite previously written tracks in one direction only. Part of the overwritten tracks, such as their edges, are preserved as the recorded data. In shingle recording, the size of the main pole 20 may be increased for a given track size. However, in order to mitigate issues such as track edge curvature, shingle writers have very narrow side gaps 14. Other design requirements may also be present. The magnetic transducer 10 may not perform as desired or meet the design requirements for such recording schemes. Without such recording schemes, the conventional transducer 10 may not adequately perform at higher areal densities. Accordingly, what is needed is a system and method for improving the performance of a magnetic recording head.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts an ABS view of a conventional magnetic recording head.

FIG. 2 depicts a flow chart of an exemplary embodiment of a method for providing a magnetic recording transducer having an asymmetric gap and asymmetric shields.

FIGS. 3A, 3B and 3C depict side, ABS and apex views of an exemplary embodiment of a magnetic recording disk drive having an asymmetric gap and asymmetric shields.

FIG. 4 depicts a flow chart of another exemplary embodiment of a method for providing an asymmetric side gap.

FIG. 5 depicts an ABS view of another exemplary embodiment of a magnetic recording transducer.

FIG. 6 depicts a flow chart of another exemplary embodiment of a method for providing a magnetic recording transducer having an asymmetric gap and asymmetric shields.

FIGS. 7 through 21 depict ABS views of an exemplary embodiment of a magnetic recording transducer fabricated using the method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 depicts an exemplary embodiment of a method 100 for providing a magnetic recording transducer. For simplicity, some steps may be omitted, interleaved, combined and/or performed in another order. The method 100 is described in the context of providing a magnetic recording disk drive and transducer 200. However, the method 100 may be used to fabricate multiple magnetic recording transducers at substantially the same time. The method 100 is also described in the context of particular layers. A particular layer may include multiple materials and/or multiple sub-layers. The method 100 also may start after formation of other portions of the magnetic recording head. For example, the method 100 may start after a read transducer, return pole/shield and/or other structure have been fabricated.

An intermediate layer including at least multiple sublayers is provided, via step 102. In at least the region in which the pole tip and side shields are to be formed (shield region), the intermediate layer includes a first sublayer, a second sublayer and at least one etch stop layer between the first and second sublayers. In some embodiments, the first and second sublayers include the same material, such as aluminum oxide or silicon oxide. In other embodiments, the first and second sublayers may include different material(s). The etch stop layer is resistance to an etch (such as a wet etch) of the second sublayer. In some embodiments, for example, the etch stop layer may include silicon nitride and/or silicon oxide. The etch stop layer may also be thin. For example, the etch stop layer may be 8-12 nm thick. In some embodiments, step 102 includes full-film depositing a first layer, full film depositing an etch stop layer and full film depositing a second layer. In an embodiment, the portions of these layers outside of the side shield region and pole tip region may be removed. The first and second sublayers and etch stop layer may thus remain in the side shield region. The third sublayer may then be deposited and the layer(s) planarized. Thus, the intermediate layer may be formed.

A trench is formed in an intermediate layer using one or more etches, via step 104. The trench formed has the desired geometry and location for formation of the main pole. For example, the top of the trench may be wider than the bottom so that the top of the main pole may be wider than the bottom. The trench extends at least partially into the first sublayer in the shield region. In some embodiments, some or all of the trench may extend through the first sublayer. However, if a leading edge bevel is desired, the bottom of the trench may slope in the down track direction. In such embodiments, the portion of the trench at the ABS may not extend through the first sublayer. However, apertures that are the upper portions of the trench are generally formed in the second sublayer and etch stop layer.

The main pole is provided in the trench, via step 106. In some embodiments, step 106 includes depositing a seed layer, such as Ru and/or magnetic seed layer(s). High saturation magnetization magnetic material(s) are also provided. For example, such magnetic materials may be plated and/or vacuum deposited. The material(s) may be planarized. Further, a trailing bevel may be formed in the main pole. Formation of the trailing bevel may include covering a portion of the main pole recessed from the ABS and then ion milling the main pole at an angle from the down track direction. This step may be performed after formation of the side shields. The pole formed in step 106 may be conformal to the trench, nonconformal with the trench, or include both conformal and nonconformal portions.

An asymmetric gap is provided, via step 108. The asymmetric gap terminates at different distances from the top of the pole on the sides of the main pole. In addition, the gap may be thicker on one side of the pole than on the other side of the main pole. Formation of the gap in step 108 may include covering the pole and the intermediate layer on one side of the main pole. The second sublayer is removed on the exposed side of the main pole in the side shield region. Thus, the etch stop layer may be exposed in this region. A nonmagnetic gap layer, such as Ru is deposited after removal of the mask. Another portion of the intermediate layer on the opposite side of the main pole may be removed. A second nonmagnetic layer may be deposited in at least the side shield region. The second nonmagnetic layer may also be Ru. The first and second nonmagnetic layers may form the asymmetric gap on the first side and top of the main pole. The second nonmagnetic layer may form the asymmetric gap on the second side of the main pole. The top of the asymmetric gap extends closer to the top of the main pole on the first side than on the second side. The bottom of the asymmetric gap may be on the etch stop layer on both sides of the main pole. The asymmetric gap is also thicker on the first side than on the second side.

The asymmetric shield(s) are provided in the shield region, via step 110. Step 110 may include plating or otherwise providing the material(s) for the side shields. Because the gap is asymmetric, the bottom of the side shields extend different distances along the sides of the main pole on the first side than on the second side. The asymmetric shield terminates on top of the asymmetric gap. Thus, the asymmetric side shield extends closer to the bottom of the main pole on the second side than on the first side. In some embodiments, the asymmetric shield terminates between the top and bottom of the main pole on both sides of the pole. Thus, the asymmetric shield(s) may be termed asymmetric half side shields. Note, however, that the asymmetric shields need not extend precisely halfway down between the top and bottom of the main pole on either side of the main pole. Instead, the asymmetric side shields may terminate somewhere between the top and bottom of the main pole. In some embodiments, the asymmetric shield may be configured such that the asymmetric shield terminates at or above the top of the main pole on the first side.

Using the method 100, a magnetic transducer having improved performance may be fabricated. A shingle writer may not need to have side shield(s) which extend to the bottom of the main pole. Thus, the method 100 may provide a main pole that may be used in shingle recording. Thus, the benefits of shingle recording may be exploited. The location of the bottom of the asymmetric shields may be set by the thicknesses of the first and second gap layers as well as the location of the etch stop layer. Thus, the side shield geometry may be tailored.

FIGS. 3A, 3B and 3C depict various views of a transducer 200 fabricated using the method 100. FIG. 3A depicts a side view of the disk drive. FIGS. 3B and 3C depict ABS and apex (side/cross-sectional) views of the transducer 200. For clarity, FIGS. 3A-3C are not to scale. For simplicity not all portions of the disk drive and transducer 200 are shown. In addition, although the disk drive and transducer 200 are depicted in the context of particular components other and/or different components may be used. For example, circuitry used to drive and control various portions of the disk drive is not shown. For simplicity, only single components are shown. However, multiples of each components and/or their sub-components, might be used. The disk drive 200 may be a perpendicular magnetic recording (PMR) disk drive. However, in other embodiments, the disk drive 200 may be configured for other types of magnetic recording included but not limited to heat assisted magnetic recording (HAMR).

The disk drive includes a media 202, and a slider 204 on which a transducer 200 have been fabricated. Although not shown, the slider 204 and thus the transducer 200 are generally attached to a suspension. In general, the slider 204 includes the write transducer 200 and a read transducer (not shown). However, for clarity, only the write transducer 200 is shown.

The transducer 200 includes an underlayer 206, an intermediate layer 208, a main pole 210, coil(s) 220, asymmetric gap 230 and asymmetric shields 240. The underlayer 206 may include a bottom (or leading edge) shield. The coil(s) 220 are used to energize the main pole 210. Two turns are depicted in FIG. 3A. Another number of turns may, however, be used. Note that only a portion of the coil(s) 210 may be shown in FIG. 3A. If, for example, the coil(s) 220 is a spiral, or pancake, coil, then additional portions of the coil(s) 220 may be located further from the ABS. Further, additional coils may also be used.

The intermediate layer 208 may include one or more sublayers as well as an etch stop layer. However, one or more of the sublayers may have been removed for formation of the asymmetric gap 230 and asymmetric shields 240. Further, the intermediate layer may also include different layers in regions recessed from the ABS.

The main pole 210 is shown as having a top wider than the bottom. The main pole 210 thus includes sidewalls having sidewall angles that are greater than or equal to zero. In an embodiment, these sidewall angles differ at different distances from the ABS. In some embodiments, the sidewall angles at the ABS are at least three degrees and not more than fifteen degrees. In other embodiments, other geometries may be used. For example, the top may be the same size as or smaller than the bottom. The sidewall angles may vary in another manner including, but not limited to, remaining substantially constant. The main pole 210 may be being conformal with the trench in the intermediate layer 208. In other embodiments, however, at least a portion of the main pole 210 may not be conformal with the sides of the trench. In some embodiments, the main pole 210 may have leading surface bevel 212 and/or a trailing surface bevel 214, as shown in FIG. 3C.

As can be seen in FIG. 3B, the gap 230 is asymmetric. Thus, the gap on one side of the pole 210 is larger than the part of the gap on the other side of the main pole 210. In addition, one side of the gap 230 terminates further from the bottom of the main pole 210 than the other.

The asymmetric shields 240 are shown as including a trailing shield portion and half side shield portions. In other embodiments, the trailing shield portion may be omitted. This is denoted by a dotted line in FIG. 3B. Further, because the asymmetric shields 240 extend different distances along the sidewalls of the main pole 210, the dashed lines in FIG. 3C indicate the side portions of the asymmetric shields 240 on opposite sides of the pole. The asymmetric shields 240 are also shown as having a constant thickness in FIG. 3C. Stated differently, the bottoms of the asymmetric shields 240 are substantially perpendicular to the ABS. Thus, the dashed line corresponding to the bottoms of the asymmetric shields 240 are perpendicular to the ABS. In other embodiments, the geometry of the asymmetric shields 240 may vary. For example, the bottom of the asymmetric shields 240 track the trailing edge of the pole such that the shield covers less of the pole further from the ABS. In other embodiments, the asymmetric shield thickness may vary. In such embodiments, the bottom of the half shield portion of the shield 240 may be parallel to the leading bevel 212 or the trailing bevel 214 while the top surface is perpendicular to the ABS. Other variations are also possible. However, note that bottoms of the asymmetric shields reside on the top of the intermediate layer 208 is between the top and bottom of the pole 210.

The magnetic transducer 200 in the disk drive may be used in shingle recording. Thus, the benefits of shingle recording may be achieved. For example, higher areal density recording may be performed by a head having larger critical dimensions.

FIG. 4 depicts an exemplary embodiment of a method 120 for providing an asymmetric gap for a magnetic recording transducer. For simplicity, some steps may be omitted, interleaved, performed in another order and/or combined. The method 120 may be used to fabricate multiple magnetic recording heads at substantially the same time. The method 120 may also be used to fabricate other magnetic recording transducers. The method 120 is also described in the context of particular layers. A particular layer may include multiple materials and/or multiple sub-layers. The method 120 also may start after formation of other portions of the magnetic recording transducer. For example, the method 120 may start after at least a portion of the pole has been fabricated.

A portion of the intermediate layer adjacent to one side of the pole is removed, via step 122. In some embodiments, step 122 includes providing a mask that covers the pole and another portion of the intermediate layer along the second, opposite side of the pole. The portion of the intermediate layer may be removed via a wet etch or, in some embodiments, another process such as an RIE. The etch terminates at the etch stop layer. Thus, the second sublayer along the first side of the pole may be removed. The mask may then be removed.

A first nonmagnetic layer is then provided, via step 124. Step 124 may include depositing a Ru layer, for example via chemical vapor deposition, sputtering or another method. In some embodiments, the first nonmagnetic layer extends across the top of the pole. In other embodiments, the first nonmagnetic layer is only on the first side of the pole. For example, the layer may be provided before removal or the mask or the portion of the layer on the top of the pole may be removed. A portion of the first nonmagnetic layer may also reside on the etch stop layer. In some embodiments, step 124 may include refilling the region adjacent to the first side of the main pole with a nonmagnetic material, such as aluminum oxide. Such a refill step may be used to provide a more flat topography for subsequent steps.

A portion of the intermediate layer adjacent to the second side of the main pole is removed, via step 126. Step 126 may be performed in an analogous manner to step 122. Thus, the etch stop layer may be exposed along the second side of the main pole. In some embodiments, the top of the first nonmagnetic layer is exposed along the first side of the main pole.

A second nonmagnetic layer is provided, via step 128. Step 128 may be analogous to step 124. For example, a Ru layer may be deposited. In some embodiments, the first and second nonmagnetic layers have different thicknesses. For example, the first nonmagnetic layer may be thicker than the second nonmagnetic layer. In other embodiments, the thicknesses may be the same. Fabrication of the magnetic transducer may then be completed.

FIG. 5 depicts an ABS view of a transducer 200′ having an asymmetric gap fabricated using the method 120. For clarity, FIG. 5 is not to scale. For simplicity not all portions of the transducer 200′ are shown. Although the transducer 200′ is depicted in the context of particular components, other and/or different components may be used. For example, circuitry used to drive and control various portions of the transducer is not shown. For simplicity, only single components are shown. However, multiples of each components and/or their sub-components, might be used. The transducer 200′ may be a PMR transducer. However, in other embodiments, the transducer 200′ may be configured for other types of magnetic recording included but not limited to HAMR.

The transducer 200′ is analogous to the transducer 200 and disk drive depicted in FIGS. 3A-3C. Consequently, analogous components have similar labels. For example, the transducer 200′ includes an underlayer 206, intermediate layer 208, pole 210′, gap 230′ and shield 240′ analogous to the underlayer 206, intermediate layer 208, pole 210, gap 230 and shield 240 of FIGS. 3A-3D.

As can be seen in FIG. 5, the asymmetric gap 230′ includes two nonmagnetic layers 232 and 234. The magnetic layer 232 is only on the first (right) side of the main pole 210′. The second nonmagnetic layer 234 covers both sides and the top of the main pole 210′. Thus, the first nonmagnetic layer 232 may be provided in step 124, while the second nonmagnetic layer 234 may be provided in step 128. In other embodiments, the first nonmagnetic layer may cover the top and both sides of the main pole 210 while the second nonmagnetic layer 234 may cover only one side of the main pole. In addition, the second nonmagnetic layer 234 that also forms the top, write gap is depicted as thinner than the first nonmagnetic layer 232. However, in other embodiments, the relationship between the thicknesses of the layers 232 and 234 may be different. The shield 240′ is also asymmetric. The portion of the shield 240′ on the first side of the main pole 210′ terminates closer to the top and is further from the main pole 210′.

The magnetic transducer 200′ in the disk drive may be used in shingle recording. Thus, the benefits of shingle recording may be achieved. For example, higher areal density recording may be performed by a head having larger critical dimensions.

FIG. 6 depicts an exemplary embodiment of a method 150 for providing a pole for a magnetic recording transducer having asymmetric side gap and shield. For simplicity, some steps may be omitted, interleaved, performed in another order and/or combined. The method 150 is also described in the context of providing a magnetic recording transducer 250 depicted in FIGS. 7-21 depict ABS views of an exemplary embodiment of a transducer 250 during fabrication using the method 150. The method 150 may be used to fabricate multiple magnetic recording heads at substantially the same time. The method 150 may also be used to fabricate other magnetic recording transducers. The method 150 is also described in the context of particular layers. A particular layer may include multiple materials and/or multiple sub-layers. The method 150 also may start after formation of other portions of the magnetic recording transducer. For example, the method 150 may start after a read transducer, return pole/shield and/or other structure have been fabricated.

The material(s) for the first sublayer are full-film deposited, via step 152. In some embodiments, step 152 includes full-film depositing aluminum oxide. The materials for the etch stop layer are provided, via step 154. Step 154 may include full-film depositing silicon dioxide or another material that is resistant to an aluminum oxide wet etch. The material(s) for the second sublayer are provided, via step 156. Step 156 may include full-film depositing aluminum oxide on the silicon oxide layer. In addition, steps 152, 154, and 156 may be carried out so that the structure including two sublayers separated by the etch stop layer are only in the shield region. FIG. 7 depicts an ABS view of the transducer 250 after step 156 has been performed. Thus, the first sublayer 262 has been provided on the underlayer 252. The etch stop layer 264 has been deposited on the first sublayer 262. The second sublayer 266 has been provided on the etch stop layer 264. Thus, the first sublayer 262 and second sublayer 266 may be aluminum oxide while the etch stop layer 264 may be silicon oxide. Other materials may be used, but the first and second sublayers are generally desired to be removable using the same etch. The etch stop layer 264 is desired to be resistant to at least some etches of the layer 262 and 266, but removable using other etches that are the same as for the layers 262 and 266. For example, a particular wet etch that would remove the first sublayer 262 and the second sublayer 266 would not remove the etch stop layer 254. However, other etches, such as a chlorine based or fluorine based RIE may remove layers 262, 264 and 266. The layers 262, 264 and 266 form at least part of the intermediate layer 260. The total thickness of the intermediate layer 260 may be at least that desired for the main pole. The etch stop layer 264 is desired to be thin, for example eight to twelve nanometers. In some embodiments, the etch stop layer 264 is nominally ten nanometers thick. The thicknesses of the layers 262, 264 and 266 may be designed such that the asymmetric gap resides on the top of the etch stop layer 264 at the desired height. Also shown is underlayer 252. The underlayer 252 may include two sublayers. A portion of the underlayer 252 at and near the ABS may be a NiFe layer used as a leading shield, while a portion of the underlayer recessed from the ABS may be a Ru layer. However, in other embodiments, other configurations, including other material(s) may be used.

A trench is formed in the intermediate layer, via step 158. Step 158 may include multiple substeps. For example, a mask including an aperture that corresponds to a trench may be provided on the intermediate layer 260. This may be accomplished using a photoresist line mask. For example, first and second hard mask layers, such as Ta and Ru, may be full film deposited. The Ta mask layer and the Ru mask layer may each be nominally fifty nanometers thick. A photoresist mask having a line corresponding to the region of the pole near the ABS is then fabricated on the first and second hard mask layers. A third hard mask layer, such as Ta, may be provided on the first and second hard mask layers and the photoresist mask. This hard mask layer may be a Ta layer that is nominally twenty nanometer thick. The photoresist mask is then removed. The location of the photoresist mask forms the location of the aperture in the hard mask layers. The photoresist mask removal may be carried out by side milling the photoresist mask to remove the third hard mask layer, then performing a lift off. A trench is formed in region of the intermediate layer 260 that is exposed by the aperture in the hard mask layers. Step 166 may include performing an aluminum oxide RIE (or other RIE(s) appropriate for the layers 262, 264 and 266). This RIE may remove the hard mask layers under the aperture in the third hard mask layer or these hard mask layers may be removed in another manner. In some embodiments, multiple RIEs are used to obtain the desired trench profile for various regions of the transducer 250. For example, fluorine-based and/or chlorine-based RIE(s) may be performed. FIG. 8 depicts an ABS view of the transducer 250 after step 158 has been performed. Thus, a trench 277 has been formed in layers 262′, 264′ and 266′ (in intermediate layer 260′). In the embodiment shown, the bottom of the trench 277 does not reach the underlayer 252 at the ABS. Thus, apertures are formed in layers 264′ and 266′, but a groove formed in at least part of the layer 262′. However, the trench 277 may be deeper at other regions, such as in the yoke region. Thus, the pole being formed may have a leading edge bevel. In addition, the trench 277 has a triangular profile at the ABS. In other embodiments, the bottom of the trench 277 has a flat surface and, therefore, a trapezoidal shape at the ABS. The trench 277 resides below an aperture in the mask 270. The mask 270 includes layers 272 and 274. In the embodiment shown, a third hard mask layer may have been removed during formation of the trench 277. In other embodiments, other masks 270 may be used.

Seed layer(s) that are resistant to an etch of the intermediate layer 260 is deposited in the trench, via step 160. In some embodiments, this seed layer may serve as at least part of the gap. The seed layer may include material(s) such as Ru deposited using methods such as chemical vapor deposition. In other embodiments, a magnetic seed layer may be used in lieu of or in addition to a nonmagnetic seed layer.

The material(s) for the main pole may then be provided, via step 162. Step 162 includes depositing high saturation magnetization magnetic material(s), for example via electroplating. In some embodiments, the pole materials provided in step 162 fills the trench 277. However, in other embodiments, the pole may occupy only a portion of the trench. FIG. 9 depicts an ABS view of the transducer 250 after a step 162 has been performed. Thus, the seed layer 279 and pole materials 280 have been provided. A leading bevel may be naturally formed in the magnetic pole to the shape of the trench 277 and the deposition techniques used.

A planarization, such as a chemical mechanical planarization (CMP) may also be performed, via step 164. In some embodiments, a trailing edge (top) bevel may be formed at this time. In other embodiments, however, the trailing bevel may be formed layer. A mill may also be used to remove the mask 270. FIG. 10 depicts an ABS view of the transducer 250 after step 164 has been completed. Thus, the portion of the main pole materials outside of the trench has been removed, forming main pole 280.

A portion of the intermediate layer 260 adjacent to the first side of the main pole 280 may be removed, via step 166. In particular, a portion of the second sublayer adjacent to the first side of the main pole 280 may be removed in at least the region in which the shields are to be formed. Step 166 includes providing a mask that covers the main pole 280 and the second sublayer on the second side of the main pole 280. In some embodiments, the removal of the second sublayer may be performed using a wet etch, such as an aluminum oxide wet etch. After the etch, the mask may be removed. FIG. 11 depicts the transducer 250 during step 166. Thus, the photoresist mask 282 and hard mask 281 are shown covering the main pole 280 and portion of the second sublayer 266″ on the opposite side of the main pole 280. The second sublayer has been removed from the first side of the main pole 280. Thus, the remaining intermediate layer 260″ includes the first sublayer 262′, the etch stop layer 264′ and the second sublayer 266″. The seed layer 279, etch stop layer 264′ and masks 281 and 282 are barriers against the etch used in step 166. FIG. 12 depicts the transducer after step 166 has been performed. Thus, the masks 281 and 282 have been removed.

A first nonmagnetic layer for the asymmetric gap is provided, via step 168. Step 168 includes depositing a Ru layer, for example via chemical vapor deposition. FIG. 13 depicts and ABS view of the transducer after step 168 has been performed. Thus, nonmagnetic layer 292 is shown. Thus, on the first side of the main pole 280, the gap would be formed by at least the seed layer 279 and the nonmagnetic layer 292.

The region above the portion of the first nonmagnetic layer 292 that is lower than the top of the pole 280 is desired to be refilled. Thus, a sacrificial layer is provided, via step 170. Step 170 may include depositing an aluminum oxide layer and then planarizing the layer. FIG. 14 depicts an ABS view of the transducer 250 after the deposition of sacrificial layer 293. Step 170 may be completed by the planarization, which exposes the top of the first nonmagnetic layer 292 on top of the main pole 280. FIG. 15 depicts an ABS view of the transducer 250 after step 170 is completed. Thus, the portion of the sacrificial layer 293′ on the first side of the main pole remains.

A trailing bevel may optionally be provided in step 172. Step 172 may include removing the portion of the first nonmagnetic layer 292 on top of the main pole 280, for example via an ion mill. A mask the covers part of the main pole 280 recessed from the ABS but leaves the portion of the main pole near the ABS uncovered may then be formed. For example, a Ru layer may be full film deposited, then patterned using a photoresist mask that is recessed from the ABS. An ion mill may then be performed. Because of shadowing due to the masks, the top of the main pole 280 may be removed such that the top of the main pole 280 is at a nonzero angle from a direction perpendicular to the ABS. Other methods could also be used to form the trailing bevel. FIG. 16 depicts an ABS view of the transducer 250 after step 172 has been completed. Thus, a portion of the first nonmagnetic layer 292′, refill 293″ and second sublayer 266″ remains. In addition, the pole 280 is shorter at the ABS than previously.

The portion of the second sublayer 266″ that is adjacent to the second side of the main pole 280 is removed in at least the region in which the shields are to be formed, via step 174. Also in step 174, the refill 293′ may be removed in at least the region in which the shields are to be formed. Step 174 may include multiple substeps. For example, a mask that covers the main pole 280 but uncovers portions of the intermediate layer 260′ and refill 293′ is provided. FIG. 17 depicts an ABS view of the transducer 250 after the mask has been provided. Thus, a nonmagnetic layer 294 and a resist mask 295 are shown. An etch that removes the desired portions of layers 266″ and 293′ is performed. For example, an aluminum oxide wet etch may be used. In other embodiments multiple etches may be performed to remove the desired portions of layers 266″ and 293′. FIG. 18 depicts an ABS view of the transducer 250 after this wet etch has been carried out. Thus, the top of the etch stop layer 264′ is exposed on the second side of the main pole 280, while the top of the first nonmagnetic layer 292′ is exposed on the first side of the main pole 280. The mask layers 294 and 295 may then be removed. FIG. 19 depicts an ABS view of the transducer 250 after step 174 is completed. Thus, the portions of layers 264′ (on the second side of the main pole 280), 292′ (on the first side of the main pole) and 279 (at the edges of the main pole 280) as well as the main pole 280 are exposed.

A second nonmagnetic layer that is to form part of the asymmetric gap is deposited, via step 176. Step 176 may include depositing a nonmagnetic layer using chemical vapor deposition, sputtering, plating or another method. FIG. 20 depicts an ABS view of the transducer 250 after step 176 is carried out. Thus, a nonmagnetic layer 296 is deposited. The nonmagnetic layer 296 may also form all or part of the write gap as it resides on the trailing surface of the main pole 280. The asymmetric gap 298 may be considered to be formed by layers 292′, 296 and 279.

The asymmetric shield(s) may be provided, via step 178. Step 178 may include depositing a seed layer as well as the material(s) for the shields. For example, a seed layer may be deposited, followed by electroplating of a magnetic material such as NiFe. In some embodiments, the asymmetric shields are part of a wraparound shield. Thus, step 178 may also include providing a wraparound shield. If the layer 296 is not to form the write gap, then a write gap layer may also be provided. FIG. 21 depicts an ABS view of the transducer 250 after step 178 has been performed. Thus, the asymmetric shield 300 is shown. As can be seen in FIG. 21, the shield 300 terminates closer to the trailing surface of the main pole 280 on the first side than on the second side of the main pole 280. This is because of the presence of the asymmetric gap 298. The asymmetric shield 300 also includes a trailing shield portion above the top/trailing surface of the main pole 280. Thus, the asymmetric shield 300 may be considered a wraparound shield. In other embodiments, the trailing portion of the shield 300 might be removed.

Using the method 150, the transducer 250 including shield 300 may be provided. Thus, the benefits of shingle recording may be achieved. For example, higher areal density recording may be performed by a head having larger critical dimensions. 

We claim:
 1. A magnetic transducer having air-bearing surface (ABS) comprising: an intermediate layer having a trench therein; a main pole, a portion of the main pole residing in the trench, the main pole having a bottom, a top wider than the bottom, a first side and a second side opposite to the first side; an asymmetric gap a first portion of the asymmetric gap along the first side of the main pole, a second portion of the asymmetric gap along the second side of the main pole, and a third portion of the asymmetric gap along the top of the pole, the asymmetric gap terminating between the top and the bottom of the main pole, first portion of the asymmetric gap terminating closer to the top of the main pole than the second portion of the asymmetric gap, the first portion of the asymmetric gap having a first thickness, the second portion of the asymmetric gap having a second thickness, the second thickness being different from the first thickness; and an asymmetric shield on the asymmetric gap, the asymmetric shield including a half side shield, a bottom of the half side shield being between the top and the bottom of the main pole and terminating on the asymmetric gap.
 2. The magnetic recording transducer of claim 1 further comprising: a leading shield.
 3. The magnetic recording transducer of claim 1 wherein the second thickness is less than the first thickness.
 4. The magnetic recording transducer of claim 1 wherein the intermediate layer further includes: an etch stop layer, a first portion of the etch stop layer residing under the first portion of the asymmetric gap, a second portion of the etch stop layer residing under the second portion of the asymmetric gap.
 5. The magnetic recording transducer of claim 1 wherein the asymmetric gap further includes a third portion and a fourth portion, the third portion adjoining the first portion and extending in a cross track direction, the fourth portion adjoining the second portion and extending in the cross track direction.
 6. The magnetic recording transducer of claim 5 wherein the asymmetric shield includes a trailing shield, the trailing shield is magnetically coupled with the half side shield such that the trailing shield and the half side shield form a wraparound shield. 